In pregnancy, we saw that low impact exercises are best including swimming, brisk walking, indoor cycling and even low impact aerobics. However, any exercise in pregnancy must be moderated. As one exercises, blood is shifted away from the internal organs (including the uterus) to the muscles, lungs and heart which require more oxygen during the exercise session. This means that strenuous exercises increase this shift of blood flow, which may restrict the oxygen to the uterus and to the baby. It is therefore important to adhere to the recommended heart rate levels during exercise to ensure adequate blood flow to the uterus and the baby.
Exercises to avoid during pregnancy
Generally, it is important to remember that the centre of balance shifts as pregnancy progresses and the abdomen descends. This increases the likelihood of falls and therefore caution is advised during any type of exercise. That being said, there are some specific exercises that should be avoided because of their particular risk to the mother or the baby. The types of exercises to avoid include:

Contact sports such as football, volleyball, softball and basketball – these carry the risk of direct trauma to the mother and the baby.

Horseback riding

Exercises that require extensive hopping, jumping, and running

Exercise that require waist twisting movements

Sky diving and scuba diving, even for the adventurous mothers. These sports are associated with changes in atmospheric pressure which may result in altitude sickness or decompression sickness.

Walking or jogging on rough terrain as these increases the risk of ankle injury.

Strenuous exercise requiring a lot of oxygen uptake, especially in the later stages of pregnancy.

When should one NOT exercise in pregnancy?
There are some medical conditions which may necessitate the avoidance or deferral of exercise during pregnancy. This underscores the need to inform your doctor or health care giver of any exercise regime one intends to undertake during pregnancy.
If you have any of the following conditions or symptoms, then exercise may not be recommended or may be deferred by you health care provider to a later date:

Asthma – exercise can trigger an acute asthmatic attack in some people, and the difficulty in breathing and resultant reduction in oxygen supply is more risky in pregnancy.

Heart disease – pregnancy places higher demands on the heart to circulate blood and oxygen, and so does exercise. The two combined are risky hence the need to cut back on exercise.

Vaginal bleeding or spotting – this may indicate a threatened abortion

A history of recurrent miscarriage

Incompetent cervix – this is a condition that causes the cervix to dilate before labor, which may lead to miscarriage. This may be exacerbated by exercise, therefore increasing the risk of miscarriage.

Low hemoglobin level (anaemia) – hemoglobin transports oxygen to all body tissues including the uterus and the baby. A very low hemoglobin level therefore means that the increased oxygen required during exercises especially in pregnancy.

Joint or muscular diseases – these may be exacerbated by exercise especially considering the increased weight during pregnancy.

High blood pressure – exercise increases blood pressure and this increase can be risky for the mother and the baby.

Small baby for the dates of the pregnancy – with the shift of blood flow from organs including the uterus during exercise, the development of a baby who is small for dates may be further hampered.

Multiple pregnancy e.g. twin pregnancy – these are associated with higher requirements than single pregnancies. These requirements e.g. oxygen, are further increased in exercise and therefore in some cases, it may be advisable to reduce exercise especially at the later stages.

Not all mothers with any of these conditions must discontinue exercise. It is therefore crucial to keep your health care provider informed on any exercise you undertake or intend to undertake throughout your pregnancy for specific, personalized advice.